Sprocket Washer Bent?

[YamFazFan]

According to information contained in the 'Lost your front sprocket and washer?' thread, a number of output shafts could be found to be slightly undersized when the outside diameter of the threaded part was measured, resulting in the threads on the nut not engaging as well as could be expected with the shaft threads. Would this explain why some bikes have done many miles on the original nut with no issues?? (ie: the output shaft diameter on these bikes is up to spec?).